chemical changes occur when a substance combines with another to form a new substance called chemical synthesis or alternatively chemical decomposition into two or more different substances these processes are called chemical reactions and in general are not reversible except by further chemical reactions
Large minerals are created from magma, when magma rises to the Earth's surface it cools slowly. As the magma cools, solid rocks form. Rocks are mixtures of minerals. Granite is a common rock that forms when magma cools. It contains the minerals quartz, plagioclase feldspar, and potassium feldspar. The different colored speckles in the granite are the crystals of the different minerals. The mineral crystals are large enough to see because the magma cools slowly, which gives the crystals time to grow.
Small minerals are created from lava, since lava is on the Earth's surface so it cools quickly compared to magma on Earth. Hence, rocks form quickly and mineral crystals are very small. Sometimes, lava cools so hastily that crystals cannot form at all, forming a black glass called obsidian. Because obsidian is not crystalline, it is not a mineral.
NOTE: Minerals (and gems) are crystals.
The balanced equation for the above reaction is as follows;
2H₂ + O₂ --> 2H₂O
stoichiometry of O₂ to H₂O is 1:2
number of O₂ moles reacted - 40.3 g / 32 g/mol = 1.26 mol
according to molar ratio
number of water moles produced = 2 x number of O₂ moles reacted
number of water moles formed - 1.26 x 2 = 2.52 mol
mass of water produced = 2.52 mol x 18 g/mol = 45.4 g
45.4 g of water produced
